Humans have different blood types – A, B, AB and O. Type O is a universal donor meaning anyone can receive it, but Type O can only receive Type O blood. Type AB is a universal acceptor meaning any blood type can be accepted but AB can only donate to their own type.
Dogs have a number of different blood types, 8 basic ones, but they are different than human types. They don’t have natural antibodies against other blood types. A reaction to a transfusion is unlikely. However if it does o0ccur, there is the possibility of a reaction being repeated if more than one transfusion is necessary.
Although dogs can usually receive any type of blood, it is advisable to type their blood so that if another transfusion is needed, a reaction can be prevented..
Cats have 3 basic blood types, A, B and AB. Type AB is rare but can be found in some breeds. Unlike dogs, cats have natural antibodies against other blood types. Reactions vary – Type A given to Type B can cause serious reactions. Reactions of Type B given to Type A are usually mild. Type AB can be given to either A or B. Type A is the most common blood type in cats. About 90-95% of cats have this type. Cats need to be typed before receiving a transfusion to avoid a reaction.
Other mammals, fish, birds and reptiles have different blood types too, although not the same as human blood types.